Can you check the task attempt logs in your cluster and find out what is happening in the reduce phase. By default task attempt logs present in $HADOOP_LOG_DIR/userlogs/<job-id>/. There could be some bug exist in your reducer which is leading to this output.
Thanks Devaraj ________________________________________ From: Arko Provo Mukherjee [arkoprovomukher...@gmail.com] Sent: Tuesday, April 17, 2012 2:07 PM To: mapreduce-user@hadoop.apache.org Subject: Re: Reducer not firing Hello, Many thanks for the reply. The 'no_of_reduce_tasks' is set to 2. I have a print statement before the code I pasted below to check that. Also I can find two output files part-r-00000 and part-r-00001. But they contain the values that has been outputted by the Mapper logic. Please let me know what I can check further. Thanks a lot in advance! Warm regards Arko On Tue, Apr 17, 2012 at 12:48 AM, Devaraj k <devara...@huawei.com> wrote: > Hi Arko, > > What is value of 'no_of_reduce_tasks'? > > If no of reduce tasks are 0, then the map task will directly write map output > into the Job output path. > > Thanks > Devaraj > > ________________________________________ > From: Arko Provo Mukherjee [arkoprovomukher...@gmail.com] > Sent: Tuesday, April 17, 2012 10:32 AM > To: mapreduce-user@hadoop.apache.org > Subject: Reducer not firing > > Dear All, > > I am porting code from the old API to the new API (Context objects) > and run on Hadoop 0.20.203. > > Job job_first = new Job(); > > job_first.setJarByClass(My.class); > job_first.setNumReduceTasks(no_of_reduce_tasks); > job_first.setJobName("My_Job"); > > FileInputFormat.addInputPath( job_first, new Path (Input_Path) ); > FileOutputFormat.setOutputPath( job_first, new Path (Output_Path) ); > > job_first.setMapperClass(Map_First.class); > job_first.setReducerClass(Reduce_First.class); > > job_first.setMapOutputKeyClass(IntWritable.class); > job_first.setMapOutputValueClass(Text.class); > > job_first.setOutputKeyClass(NullWritable.class); > job_first.setOutputValueClass(Text.class); > > job_first.waitForCompletion(true); > > The problem I am facing is that instead of emitting values to > reducers, the mappers are directly writing their output in the > OutputPath and the reducers and not processing anything. > > As read from the online materials that are available both my Map and > Reduce method uses the context.write method to emit the values. > > Please help. Thanks a lot in advance!! > > Warm regards > Arko